You also knew that Ko served foie gras in a way the city had never seen. A cook behind the counter would rub a frozen cured brick of it across a Microplane held above a bowl with pine nut brittle, riesling jelly and lobes of lychee, showering them with falling pink flakes of airborne pleasure.

Mr. Chang moved Ko to an alleyway off East First Street late last year, and it’s a testament to how much more polished and accomplished the new place is that when the foie gras appears toward the end of the night, it doesn’t dazzle the way it used to. In the company of another 14 or so graceful, beautiful dishes, it is slightly flat-footed, a dancer loping across the stage in Chuck Taylors while the rest of the corps balances on pointe shoes.

This is no put-down. There’s no shame in being outclassed by a firm, spiced tartare of Japanese sea bream hanging in a sparkling jelly brewed from the fish’s bones in which capsules of finger lime wait, invisibly, tiny balloons of sourness ready to pop.

Or in being cast in the shade by a one-bite mille-feuille whose crisp layers of rye pastry, sprinkled with green tea powder, hold lush yuzukosho béchamel and briny little globes of trout roe.

Or in being shown up by barely seared, gently smoked lobster tail with the juicy tenderness of a ripe, warm nectarine. Extraordinary on its own, the tail sits on a whorl of spaghetti squash that becomes uncharacteristically exciting as it drinks up a foamy lobster sauce. At last, we know what spaghetti squash is good for.

Leading the gang of cooks responsible for these plates and others is Sean Gray, Ko’s executive chef since 2014. (Mr. Chang, often seen wedged behind the counter in 2008, now presumably lurks in an underground lair somewhere, staring at a wall map with pins marking his dominion in New York, Toronto and Sydney.)

Momofuku Ko is remembered as a local pioneer of the tasting-counter format that has spread across the country, but the original ambition was bolder. Mr. Chang was leading a daring experiment that asked: If you aspired to serve food as original and refined as anything in an expensive uptown restaurant but wanted to keep prices down, exactly how many amenities could you strip out? The answer turned out to be, “Not quite that many, Dave,” but the question was the right one at the right time.

With the move, that experiment officially ended. The new Ko has amenities galore and a price to match.

The high degree of finesse in the $175 tasting menus must be due in part to the greater acreage and better equipment in the kitchen, inside a U-shaped counter that seats up to 18. As they did before the move, Mr. Gray and his colleagues take turns delivering dishes. The original crew on First Avenue rarely made eye contact and often appeared mildly resentful, an understandable reaction in those sweatshop conditions. Now, Mr. Gray and his collaborators look relaxed. Sometimes they even smile.

They’re not the only ones whose accommodations have been upgraded. We diners can settle our tense, crooked frames into the pliant leather seats and backs of the tall stools arranged around the counter, enjoying space around and behind us. This may not sound like cause to celebrate unless you remember the old Ko, where every time somebody squeezed behind you on the way to the restroom, you had to lean forward and hold your breath.

Should you arrive early to this palace of luxury, you can pause at the small and very appealing bar, where the cocktails are highly intelligent without rubbing your nose in it. After the desserts (if you are in luck, one will be a bittersweet cookie-like tart shell filled with Fernet Branca pastry cream and dark chocolate mousse), you can ask for a cup of hearty and well-rounded barley tea, a remarkable concession from Mr. Chang, who in the past seemed to regard tea as a sign of weakness.

During the meal, there is wine, in uncannily delicate glasses, from some of the world’s most revered grape stompers. Jordan Salcito, beverage director for the Momofuku group, gives these winemakers’ names and faces prominent play on her 78-page list. She also tries to show stylistic resemblances by noting when one producer has influenced another. This is a more useful, up-to-date way to choose a bottle than the ancient system of memorizing vintages and appellations. It comes at the cost, though, of emphasizing cult stars over new finds whose bottles are often bargains; there could be more choices for under $75.

Versatile wines do best with the quick shifts of flavor in the seafood-heavy menu. You don’t want anything to fight with the intense flavor of cured, citrus-glazed mackerel sushi under scallions and grated fresh ginger strands. The skin is quickly blistered with the same blowtorch used to gently toast the bottom of the rice, bringing a wonderfully un-sushi-like crunch to one of the restaurant’s most delicious creations.

Dud dishes are rare. There must be better places for exceptionally soft Osetra caviar than in a tomato-and-basil salad, for instance. (There are, and on another night the roe was spooned over an amazing, near-liquid potato purée.)

Soy milk chawanmushi and a dark blotch of intentionally burned applesauce would have been puzzling with sea urchin even if the urchin hadn’t tasted metallic and iodine-heavy. This was more surprising because I’d been served exceptional sea urchin on other nights, laid alongside a swoosh of chickpea purée that incorporates fermented chickpea paste. If I told you fermented chickpea paste tastes a little like cheese, you might not want to try it, but you should. Eaten together with the urchin, two soft and orange blobs finding each other inside your mouth, it’s like a door cracking open to a new world of flavor.

A few failures don’t necessarily derail a meal that aims this high. But you might, if you were feeling philosophical, point out that the menu’s sensibility could be more unified. Mr. Chang once called tasting menus “chefs’ novels, their big ideas, their statements of purpose and intent.” The menus at the new Ko are more like collections of short stories, not all by the same author.

Quills of trofie dressed with Tasso ham, poblano peppers and Mimolette cheese make an odd traveling companion for the mackerel sushi. Elysian Farms lamb with green tomatoes and Calabrian chiles might turn up in any number of restaurants, and so could the excellent sourdough bread. Nobody would say that about the daring chickpea and sea urchin duet.

The unifying theme of the original Ko was: “Forget your ideas of fancy dining. Here’s something new.” It was built by and for young, hungry, probably insomniac rebels who chased their craziest ideas. The new Ko was built by a mature chef for customers who have grown up, and it reflects all the comforts and resources and security and extra padding we accumulate in the middle of our lives. Those things can hem us in, putting the 4 a.m. howlings of youth out of reach, or at least making them seem counterproductive. If the new Ko has a message, it is: “Yep. This is what fancy dining is like now.” But those youthful howlings are still in its bones.